Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 252127

Area Forecast Discussion
National Weather Service North Platte NE
327 PM CST Sat Feb 25 2017

Issued at 327 PM CST Sat Feb 25 2017

A broad longwave trough of low pressure was present
across all but the east coast of the CONUS this morning. Within this
longwave trough, low pressure was present over western Michigan and
off the coast of far northern California. Between these two features,
several minor shortwaves were noted from Kansas west into Nevada.
Satellite imagery this afternoon is indicative of snow covering
almost 90 percent of Nebraska. The only snow free areas of note were
the bottom tier of counties from Benkleman to Falls City. Across
western and north central Nebraska, thick snow cover was present and
has held temperatures in the 20s this afternoon. Some lower 30s were
present along and south of Interstate 80. Even with the near
freezing temperatures south of the Interstate, a higher late
February sun angle and full sun has begun to shrink the southern
extent of the snowfield this afternoon. This snowfield will come
into play with temperatures over the next few days.


.SHORT TERM...(This evening through Sunday)
Issued at 327 PM CST Sat Feb 25 2017

Flow both at the surface and aloft will be westerly the next 24 hrs.
Deep snowpack covers about the northern 2/3 of western and north
central Nebraska, and this will continue to have an impact on
temperatures tonight and Sunday. Winds tonight will remain from the
west at around 5 mph or so, and this will be just enough to keep
lows from dropping into the single digits. The exception will be
potions of the Platte River valley, where lows may drop to near 8 or
9 degrees in spots. Northwest Nebraska will also see single digits,
otherwise lows should generally range between 10 and 15 degrees.

Sunday, westerly flow brings in slightly warmer air with 850 mb
temperatures rising 1 to 2 degrees. With the deep snowpack, highs
will struggle to get above freezing across most of northern
Nebraska, but towards the Kansas/Colorado border areas less snow
cover should allow highs to reach the mid to upper 30s. Full
sunshine is expected Sunday with very little moisture for cloud
cover in the mid and upper levels.

.LONG TERM...(Sunday night through Saturday)
Issued at 327 PM CST Sat Feb 25 2017

Temperatures followed by a small threat for light snow
Monday night are the main forecast challenges. First off with
respect to temperatures. A thick snow cover which extends from
roughly just south of the Interstate to the South Dakota border will
come into play with highs and lows at least through midweek. The
superblend forecast seemed too warm, especially with respect to
night time lows, especially in the Platte river valley. For North
Platte, the MET guidance had 17 for a low Sunday night with the MAV
guidance having 9. Given the expected snow cover, the colder MAV
guidance was utilized for this forecast. On Monday, the guidance
does come into better agreement for highs with upper 40s to around
50 forecast. These highs do assume that we do mix Monday. Looking at
forecast soundings in the MET and MAV, we only mix up to about h850
Monday afternoon. Also, there is a decent amount of moisture in the
H350 to H250 range, so high clouds may be an issue with temps as
well. So with the possibility of clouds and decreased mixing, highs
were trended more toward around 40 in the north to around 45 in the
south. That being said, forecast highs for Monday are around 5
degrees cooler than the guidance. By Monday night, a shortwave
trough of low pressure aloft will transition into the central
Rockies. This feature will force a cold front through the forecast
area late Monday Night. Behind the surface front, weak mid level
frontogenesis will spread from the Northern panhandle into
northwestern, then north central Nebraska. Lift within this area of
lift is fairly weak but strong enough with some mid level moisture
co-located to warrant at least a slight chance pop for light snow
late Monday night into Tuesday morning. At this time, will keep pops
and any snow accums on the very light side as this system is fast
moving and appears fairly moisture starved. None the less, we could
see up to an inch of snow over northern Nebraska Monday night into
Tuesday morning. The main trough of low pressure will track across
the central plains Tuesday night into Wednesday. Precipitation will
develop INVOF the surface front across Kansas into southeastern
Nebraska and Iowa. At this time, the only threat for light
precipitation is across far southwestern Nebraska Tuesday evening.
Beyond Tuesday night, cold northwesterly flow aloft will persist
through Thursday. Highs will be in the 30s to lower 40s with dry
conditions expected. By Friday, a warm front will push through the
forecast area with a ridge aloft building into the central and
northern Plains. Highs will reach back into the upper 40s and 50s
for Friday and Saturday.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1130 AM CST Sat Feb 25 2017

Other than some scattered mid and high level clouds, clear skies
are expected this afternoon through tonight. Winds will be west
around 10 kts through tonight as well. VFR conditions will prevail
all areas.




LONG TERM...Buttler
AVIATION...Taylor is the U.S. government's official web portal to all federal, state and local government web resources and services.